The United States has accused China of secretly conducting a nuclear test in 2020, revealing the allegation at a global disarmament conference in Geneva. Washington urged the creation of a new and broader arms control agreement involving both China and Russia. The claim came a day after the expiration of the New START treaty, the last active nuclear arms control pact between the US and Russia. US Under Secretary for Arms Control and International Security Thomas DiNanno said the test, allegedly conducted on June 22, 2020, had an explosive yield equivalent to hundreds of tons of TNT and was concealed by the Chinese military using seismic masking techniques.

An official from the international nuclear test monitoring organization countered that no event consistent with a nuclear explosion was detected on that date, noting their system can identify blasts of 500 tons of TNT or greater. The Chinese embassy in Washington rejected the accusation, reaffirming China’s commitment to its “no first use” policy and its moratorium on nuclear testing. Beijing called on all parties, including the US, to uphold test-ban commitments.

Analysts warned that the end of the New START treaty and renewed nuclear tensions could destabilize global power balances, underscoring the need for constructive arms control dialogue.